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Subversion Repositories openrisc_2011-10-31

[/] [openrisc/] [trunk/] [or1k_startup/] [sw/] [OR1K_startup.S] - Blame information for rev 498

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Line No. Rev Author Line
1 2 marcus.erl 
/*
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        Register usage
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        R0 = 0
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        R1 = pointer to destination
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        R2 = nr of words to be copied
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        R3 = data
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        R4 = pointer to SPI core
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        R5 = spi control word
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        R6 = jump adr
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        R7 = nr of control words
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        r8 = adr pointer
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*/
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        .equ spi_base,0xb0000000 ;
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        .equ spi_ctrl,0x0520    ;
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        .equ read_cmd, 0x03000000 ;
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        .global start           ;
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        .text
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start:
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        l.movhi r0,0x0          ;
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        l.ori r1,r0,0x0 ; # R1 = 0x0
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        l.movhi r4,hi(spi_base) ; # R4 = spi base
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        l.ori r5,r0,lo(spi_ctrl); # R5 = spi control
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        # set SPI regs, can be removed if reset state is changed in IP core
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        #l.ori r3,r0,0x420      ;
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        #l.sw 0x10(r4),r3       ; # tx at negedge, 32 bit transfer
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        #l.movhi r3,0x0300      ;
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        #l.ori r3,r3,0x0        ;
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        #l.sw 0x0(r4),r3        ; # TX = 0x03000000
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        #l.sw 0x14(r4),r0       ; # prescaler to zero
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        # set slave select active
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        l.ori r3,r0,0x1         ; # R3 = 0x1
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        # initiate SPI FLASH READ
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        l.jal read              ;
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        l.sw 0x18(r4),r3        ; # ss active
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        # read
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        l.jal read              ;
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        l.sw 0x0(r4),r0         ; # set TX to zero
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        l.or r2,r3,r3           ; # R2 = nr of words
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loop1:  l.jal read              ; # read adr pointer
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        l.addi r1,r1,0x8        ;
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        l.jal read              ; # read data
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        l.or r8,r3,r3           ; # copy adr pointer to r8
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        l.sfeq r8,r0            ;
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        l.bnf loop1             ;
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        l.sw 0x0(r8),r3         ; # write control data
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loop2:  l.jal read              ;
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        l.addi r1,r1,0x4        ;
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        l.sw 0x0(r1),r3         ; # write to RAM
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        l.sfeq r1,r2            ;
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        l.bnf loop2             ;
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        l.ori r6,r0,0x100       ;
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        l.jr r6                 ;
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        # set slave select inactive
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        l.sw 0x18(r4),r0        ; # set slave select inactive
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read:
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        l.sw 0x10(r4),r5        ; # write spi control
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w4busy: l.lwz r3,0x10(r4)       ;
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        l.sfeqi r3,lo(spi_ctrl) ;
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        l.bf w4busy             ;
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        l.nop                   ;
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        l.jr r9                 ;
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        l.lwz r3,0x0(r4)        ; # R3 = RX
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